Submission #382601

#	Time	Username	Problem	Language	Result	Execution time	Memory
382601		rainboy	Strange Device (APIO19_strange_device)	C11	30 / 100	1464 ms	106220 KiB

strange_device

#include <stdio.h>

#define N	1000000

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

long long gcd(long long a, long long b) {
	return b == 0 ? a : gcd(b, a % b);
}

long long xx[N * 2], yy[N * 4], ll_[N * 2], rr_[N * 2];

int compare_x(int i, int j) {
	return xx[i] == xx[j] ? 0 : (xx[i] < xx[j] ? -1 : 1);
}

int compare_y(int i, int j) {
	return yy[i] == yy[j] ? 0 : (yy[i] < yy[j] ? -1 : 1);
}

int compare_l(int i, int j) {
	return ll_[i] == ll_[j] ? 0 : (ll_[i] < ll_[j] ? -1 : 1);
}

int (*compare)(int, int);

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k) {
			int c = compare(ii[j], i_);

			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		}
		sort(ii, l, i);
		l = k;
	}
}

int main() {
	static long long ll[N], rr[N];
	static int ii_[N * 4], ii1[N * 2], kk[N * 2];
	int n, n_, n1, i, j, x, cnt;
	long long a, b, l, r, ans;

	scanf("%d%lld%lld", &n, &a, &b), a /= gcd(a, b + 1);
	for (i = 0; i < n; i++)
		scanf("%lld%lld", &ll[i], &rr[i]);
	n_ = 0, n1 = 0;
	for (i = 0; i < n; i++) {
		l = ll[i] / b, r = rr[i] / b;
		if (l == r)
			xx[n_] = l % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
		else {
			xx[n_] = l % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = b, n_++;
			xx[n_] = r % a, yy[n_ << 1 | 0] = 0, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
			if (r - l > 1) {
				l++, r--;
				if (r - l + 1 >= a) {
					printf("%lld\n", a * b);
					return 0;
				}
				l %= a, r %= a;
				if (l <= r)
					ll_[n1] = l, rr_[n1] = r, n1++;
				else {
					ll_[n1] = l, rr_[n1] = a - 1, n1++;
					ll_[n1] = 0, rr_[n1] = r, n1++;
				}
			}
		}
	}
	for (i = 0; i < n_; i++)
		ii_[i] = i;
	compare = compare_x, sort(ii_, 0, n_);
	for (i = 0; i < n1; i++)
		ii1[i] = i;
	compare = compare_l, sort(ii1, 0, n1);
	ans = 0;
	for (i = 0, j = 0, r = -1, x = 0; i < n_; i++) {
		while (j < n1 && ll_[ii1[j]] <= xx[ii_[i]]) {
			int i1 = ii1[j++];

			if (r < ll_[i1])
				ans += rr_[i1] - ll_[i1] + 1, r = rr_[i1];
			else if (r < rr_[i1])
				ans += rr_[i1] - r, r = rr_[i1];
		}
		xx[ii_[i]] = r >= xx[ii_[i]] ? -1 : (i + 1 == n_ || xx[ii_[i + 1]] != xx[ii_[i]] ? x++ : x);
	}
	ans *= b;
	for (i = 0; i < n_ * 2; i++)
		ii_[i] = i;
	compare = compare_y, sort(ii_, 0, n_ * 2);
	cnt = 0;
	for (i = 0; i + 1 < n_ * 2; i++) {
		int i_ = ii_[i];

		x = xx[i_ >> 1];
		if ((i_ & 1) == 0) {
			if (x != -1 && kk[x]++ == 0)
				cnt++;
		} else {
			if (x != -1 && --kk[x] == 0)
				cnt--;
		}
		ans += (yy[ii_[i + 1]] - yy[ii_[i]]) * cnt;
	}
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

strange_device.c: In function 'main':
strange_device.c:59:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   59 |  scanf("%d%lld%lld", &n, &a, &b), a /= gcd(a, b + 1);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.c:61:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   61 |   scanf("%lld%lld", &ll[i], &rr[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 5
• Subtask 5: 0 / 5
• Subtask 6: 0 / 20
• Subtask 7: 20 / 20
• Subtask 8: 0 / 30